1. A method for synthesizing cyanoacrylate comprises the following reaction processes: compound (3) is produced by reacting compound (1) with compound (2), and is characterized in that: the reaction process does not use solvent, and is carried out in a molten state,

compound (1), Compound (2), Compound (3)

R₁Selected from: c₁-C₆Alkyl radical, C₂-C₆Alkenyl radical, C₂-C₆Alkynyl, C₃-C₆Cycloalkyl, aryl, C₃-C₁₀Heterocyclic radical, C₃-C₁₀A heteroaryl ring group;

R₂is selected from C₁-C₆Alkyl radical, C₂-C₆Alkenyl radical, C₂-C₆Alkynyl, C₃-C₆Cycloalkyl, the groups of compound (1) and compound (2) are identical.

2. The method of claim 1, wherein R is₁May be optionally substituted with one or more of the following groups: hydrogen, halogen, NO₂、C₁-C₄Alkyl radical, C₂-C₄Alkenyl radical, C₂-C₄Alkynyl, C₃-C₆Cycloalkyl radical, C₁-C₄Haloalkyl, C₂-C₄Haloalkenyl, C₂-C₄Haloalkynyl group, C₃-C₆Halocycloalkyl radical, C₁-C₆Alkoxy radical, C₁-C₄Alkylamino radical, C₁-C₄Haloalkoxy, C₁-C₄Alkylthio radical, C₁-C₄Alkylsulfinyl radical, C₁-C₄Alkylsulfonyl radical, C₂-C₆Alkoxycarbonyl, C₂-C₆Alkylcarbonyl group, C₃-C₆(alkyl) Cycloalkylamino, C₂-C₆Alkylamino carbonyl, C₁-C₆Alkoxycarbonylamino group, C₂-C₈Dialkylamino group, C₃-C₆Cycloalkylamino, C₃-C₈Dialkylaminocarbonyl group, C₃-C₆Trialkylsilyl, phenyl, phenoxy, benzyl and halophenyl groups.

3. A process for the synthesis of cyanoacrylic esters as claimed in claim 2, R₁Is a benzene ring, R₂Is ethyl.

4. The method according to claim 1, wherein the reaction system contains a catalyst.

5. A cyanoacrylate synthesis process according to claim 4, wherein said catalyst is selected from organic bases.

6. The method for synthesizing cyanoacrylate as claimed in claim 5, wherein said catalyst is one or more of tertiary amine organic bases selected from triethylamine, tri-N-propylamine, pyridine, 2-methylpyridine, 4-dimethylaminopyridine, and N, N' -dimethylaniline.

7. A cyanoacrylate synthesis process according to any one of claims 1 to 6, wherein the reaction is carried out at a temperature above the melting temperature of the reaction mixture.

8. A cyanoacrylate synthesis process according to claim 7, wherein the reaction temperature is in the range 10 to 80 ℃, preferably 20 to 40 ℃ above the melting temperature of the reaction mixture.

9. A cyanoacrylate synthesis process according to any one of claims 1 to 8, wherein the reaction removes by-products by vacuum.

10. The method according to claim 3, wherein the ethyl benzoate-imide is prepared by condensing benzamide and diethyl sulfate in a solvent.

Background

The cyanoacrylate compounds have important application in the field of life science, wherein the 2-cyano-3-amino-3-phenyl acrylate derivatives are used as pesticide bactericides and have excellent control effects on wheat scab and rice bakanae disease.

The method for synthesizing the 2-cyano-3-amino acrylate mainly comprises the following methods:

method one (j.am.chem.soc. 1943, 40, 388-390):

the compound is prepared by condensing amidine and cyanoacetate, wherein the cyanoacetate and the amidine react to generate two products, the yield of a target product is only 28%, the yield of the method is low, the purification is difficult, and the reaction formula is as follows:

y＝28％

wherein R is₂Is C₁～C₆An alkyl group.

Method two (Bull Soc Chim. Fr. (1-2, Pt.2)1976, 177-83 (Fr)):

the method is prepared by directly reacting various (substituted) thiobenzoyl with 2-bromocyanoacetate, and the method has the following reaction equation:

wherein R is₂Is C₁～C₆An alkyl group;

method three (j.prakt.chem.chemie 1983, 325(5), 876-9):

the method is characterized by comprising the steps of firstly, carrying out addition reaction on 3-phenyl-2-cyanoacrylate and triethyl phosphite, then brominating and eliminating the product, and finally reacting the product with ammonia water. The reaction equation is as follows:

wherein R is₂Is C₁～C₆An alkyl group.

Method four (j.org.chem., 1973, 33(13), 2287-2290):

firstly, 3-phenyl-cyanoacrylate and chlorine are added to generate 2, 3-dichloro-3-phenyl-2-cyanoacrylate (IV),

then the reaction is eliminated in the presence of an acid-binding agent or at high temperature to obtain 3-chlorine-3-phenyl-2-cyanoacrylate (V), and finally the 3-chlorine-3-phenyl-2-cyanoacrylate and ammonia water are added

And preparing a target product. The method needs to be carried out at high temperature, and when the method is adopted for synthesis, the compound IV is cracked into the compound

V, the yield is very low, and most of the product is 2-chloro-3-phenyl acrylonitrile which is a byproduct. The reaction equation is as follows:

wherein R is₂Is C₁～C₆An alkyl group.

The method five comprises the following steps: (Synthetic communications.1993, 23(16)2293 to 2302)

Using ethyl acetate as solvent, under the condition of reflux making 3-amino-3-phenyl acrylonitrile react with phosgene to produce intermediate

3-amino-3-phenylpropionyl chloride (VI) and then C₁～C₆The fatty alcohol reacts to produce the target compound. The method uses raw materials

3-amino-3-phenyl acrylonitrile is difficult to obtain and is difficult to carry out 3-amino series in 3-amino-3-phenyl-cyanoacrylate compounds

And (4) substitution. The reaction equation is as follows:

wherein R is₂Is C₁～C₆An alkyl group.

The method six: (Synthetic communications.1996, 26(19) 3549-3557; US4781750)

Various substituted benzoyl chlorides and cyanoacetic acid esters react in the presence of alkali (such as magnesium ethoxide, sodium ethoxide or triethylamine) to obtain an intermediate 3-hydroxy-3-substituted phenyl-2-cyanoacrylate (VII), and when triethylamine is used as an acid-binding agent, the substituted benzoyl chlorides must contain strong electron-withdrawing groups, such as nitro, cyano and the like, for reaction. Chloridizing 3-hydroxy-3-substituted phenyl-2-cyanoacrylate (VII) by phosphorus oxychloride to obtain 3-chloro-3-substituted phenyl-2-cyanoacrylate (VIII), and then reacting the compound VIII with ammonia water to generate a target product, wherein the reaction equation is as follows:

。

method seven, (Journal of the Chemical Society, 1943, p.388

In the literature, although yields are not high, synthetic schemes for the preparation of 3-amino-2-cyano-3-phenylacrylate by condensation of ethyl benzoate with ethyl cyanoacetate in ethanol are given. Inspired by the above documents, the pesticide research institute CN200810235717.9 in Jiangsu province prepares the phenamacril under the catalysis of organic base in a solvent, and synthesizes a pyridyl compound in 201910146018.5. Not only improves the yield, but also realizes and realizes the industrialized production,

the reaction formula is as follows:

。

although the technical scheme of the method seven has certain advantages, the synthesis method used in the method seven is carried out in an organic solvent, and the organic solvent has potential risks to human health and environment, and the production capacity is limited.

Disclosure of Invention

The inventor researches and discovers that cyanoacrylate can be prepared by directly reacting imido ester with cyanoacetate without solvent, and although the product cyanoacrylate is solid in the reaction process, when the reaction temperature is increased to be higher than the melting point of the product, the reaction can be continued, but the problem that unreacted raw materials are included in product crystal nuclei is solved, and more importantly, the reaction can be carried out in the forward direction by removing generated small molecular compounds under high vacuum and reduced pressure in a molten state. Thereby having the following advantages: 1) the organic solvent is saved, and the potential harm of the organic solvent to human bodies and the pollution to the environment are avoided; 2) the production efficiency is improved.

The invention is implemented according to the following technical scheme:

a method for synthesizing cyanoacrylate comprises the following reaction processes: compound (3) is produced by reacting compound (1) with compound (2), and is characterized in that: the reaction process does not use solvent, and is carried out in a molten state,

R₁selected from: c₁-C₆Alkyl radical, C₂-C₆Alkenyl radical, C₂-C₆Alkynyl, C₃-C₆Cycloalkyl, aryl, C₃-C₁₀Heterocyclic radical, C₃-C₁₀A heteroaryl ring group;

R₂is selected from C₁-C₆Alkyl radical, C₂-C₆Alkenyl radical, C₂-C₆Alkynyl, C₃-C₆Cycloalkyl, the groups of compound (1) and compound (2) are identical.

As a preferred embodiment of the method for synthesizing the cyanoacrylate of the present invention, wherein R is₁May be optionally substituted with one or more of the following groups: hydrogen, halogen, NO₂、C₁-C₄Alkyl radical, C₂-C₄Alkenyl radical, C₂-C₄Alkynyl, C₃-C₆Cycloalkyl radical, C₁-C₄Haloalkyl, C₂-C₄Haloalkenyl, C₂-C₄Haloalkynyl group, C₃-C₆Halocycloalkyl radical, C₁-C₆Alkoxy radical, C₁-C₄Alkylamino radical, C₁-C₄Haloalkoxy, C₁-C₄Alkylthio radical, C₁-C₄Alkylsulfinyl radical, C₁-C₄Alkylsulfonyl radical, C₂-C₆Alkoxycarbonyl, C₂-C₆Alkylcarbonyl group, C₃-C₆(alkyl) Cycloalkylamino, C₂-C₆Alkylamino carbonyl, C₁-C₆Alkoxycarbonylamino group, C₂-C₈Dialkylamino group, C₃-C₆Cycloalkylamino, C₃-C₈Dialkylaminocarbonyl group, C₃-C₆Trialkylsilyl, phenyl, phenoxy, benzyl and halophenyl groups.

As 3-amino-3-phenyl-2-ethyl cyanoacrylate has great application value, R is a further preferable scheme of the synthetic method of cyanoacrylate of the invention₁Is a benzene ring, R₂Is ethyl.

In order to accelerate the reaction, as another preferable embodiment of the method for synthesizing cyanoacrylate of the present invention, a catalyst is added to the reaction system to accelerate the reaction. These catalysts are organic bases, in particular tertiary amines, selected from: one or more than two of triethylamine, tri-N-propylamine, pyridine, 2-methylpyridine, 4-dimethylaminopyridine and N, N' -dimethylaniline.

In general, in order to facilitate the reaction, it is preferable to control the final reaction temperature to be higher than the melting temperature of the objective compound. However, the excessive reaction temperature accelerates the occurrence of side reactions, and the reaction process of the present invention necessarily generates tri-substituted s-triazine by-products, so that the initial temperature of the reaction is controlled to be about 60 to 100 ℃ in the initial stage of the reaction, and the final temperature is controlled to be 10 to 80 ℃, preferably 20 to 40 ℃, above the melting temperature of the reaction mixture.

As a further preferred embodiment of the process for the synthesis of cyanoacrylic esters of the invention, the reaction is promoted towards the product by removing by-products in vacuo, since no solvent is present and the reaction product has a relatively high melting point and a relatively high boiling point. This advantage is not generally available in chemical reactions using common organic solvents.

Imido ester is the key intermediate of the reaction, and the process of preparing imido ester is generally that nitrile intermediate is reacted with alcohol in solvent in the presence of dry hydrogen chloride to obtain imido ester hydrochloride, which is then neutralized with alkali to obtain imido ester through filtering or no filtering, and these imido esters are purified or further reacted directly. For the synthesis of 3-amino-3-phenyl-2-cyano ethyl acrylate with great application value in the field of plant protection, the invention provides a technical scheme for preparing ethyl phenylmethaneiminate by condensation of benzamide and diethyl sulfate in a solvent.

Has the advantages that: the method for synthesizing the cyanoacrylate reduces or eliminates the harm of the traditional organic solvent to the health of personnel and the pollution of ecological environment because the molten state is adopted for reaction and the organic solvent is not used, and simultaneously greatly improves the utilization rate of equipment and improves the production efficiency.

Detailed Description

The present invention is further illustrated by the following examples, but should not be construed as being limited to the scope of the examples.

Example-1:

the first step,

The reaction formula is as follows:

the operation process is as follows: the synthesis of ethyl phenylmethaneimide is carried out with reference to the relevant literature J.heterocyclic. chem.33.1903 (1996). The operation process is as follows: 150g of hydrogen chloride gas was bubbled into a solution of about 4.0 moles of benzonitrile, 8.0 moles of ethanol in 2000ml of toluene at 5-10 deg.C. And stirred at room temperature (25 ℃) for 20 hours, and a white solid was filtered off. The white solid is dissolved in 3000 ml of absolute ethyl alcohol and neutralized by triethylamine to pH value 7-8.5, the solvent is evaporated to dryness under reduced pressure, triethylamine hydrochloride is filtered out, a filter cake is washed by 200ml of dichloromethane for 3 times, the dichloromethane and part of ethanol are removed under reduced pressure by combining filtrate and washing liquid, the residual oily matter is distilled under reduced pressure, and fraction at 102-104 ℃ is intercepted at 2mmhg to obtain 525.0g of benzimidoethyl ester, and the purity is analyzed by GC to be 98%.

The operation process is as follows: 149g (1.0 mol) of ethyl phenylmethanimidate and 113g of ethyl cyanoacetate (1.0 mol) are added into a four-mouth glass bottle of a condenser provided with a mechanical stirring thermometer, heated to 80 ℃, reacted for 2 hours at the temperature, heated to 100 ℃, kept at the temperature for 2 hours, heated to 120 ℃, kept at the temperature for 8 hours, further heated to 140 ℃, kept at the temperature for 2 hours, and simultaneously ethanol generated by the reaction is removed at the temperature under the negative pressure of 3 mmHg. After the content of ethyl phenylmethanimidate was less than 0.5%, the reaction product was decanted off, filtered under pressure in the melt to give 198g (95% by weight) of ethyl 3-amino-3-phenyl-2-cyanoacrylate, and filtered off 3.50g of triphenyls-triazine with a purity of 95% (HPLC).

Example 2:

the first step,

The reaction formula is as follows:

the operation process is as follows: in a four-necked flask equipped with a mechanical stirrer, a thermometer and a reflux condenser were charged 121g (1.0 mol) of benzamide, 169.4g (1.10 mol) of diethyl sulfate and 860g of toluene. Heating to 110-120 deg.C, reflux reacting for 4 hr, and cooling to 25 deg.C. The reaction mixture was neutralized with 5% sodium hydroxide solution to pH 7.0-8.5, the phases were separated, and the organic layer was dried over anhydrous sodium sulfate (25 g). After toluene removal, a fraction at 105 ℃ and 104 ℃ was taken out under 2mmHg by distillation under reduced pressure to obtain 130g of ethyl benzoate having a purity of 98% by GC analysis.

Step two

The reaction formula is as follows:

the operation process is as follows: 149g (1.0 mol) of ethyl phenylmethylimidate, 113g of ethyl cyanoacetate (1.0 mol) and 0.1g of DMAP (4-dimethylaminopyridine) are added into a four-mouth glass bottle of a condenser provided with a mechanical stirring thermometer, the temperature is raised to 80 ℃, the mixture reacts for 2 hours at the temperature, then the temperature is raised to 100 ℃, the temperature is kept for 2 hours, then the temperature is raised to 120 ℃, the temperature is kept for 2 hours, then the temperature is raised to 140 ℃, the temperature is kept for 2 hours, and the ethanol generated by the reaction is removed under the negative pressure of 3 mmHg. Following GC, the reaction product was decanted off until the ethyl phenylmethanimidate content was less than 0.5% and filtered under melting to give 210g of ethyl 3-amino-3-phenyl-2-cyanoacrylate, 2.3g of triphenyl s-triazine (HPLC) as insoluble material, ethyl 3-amino-3-phenyl-2-cyanoacrylate being 95% pure (GC).

Example 3

Step one

The reaction formula is as follows:

the operation process is as follows: the synthesis of ethyl phenylmethaneimide is carried out with reference to the relevant literature J.heterocyclic. chem.33.1903 (1996). 150g of hydrogen chloride gas was bubbled into a solution of about 4.0 moles of benzonitrile, 8.0 moles of ethanol in 2000ml of toluene at 5-10 deg.C. And stirred at room temperature (25 ℃) for 20 hours to give a filtered white solid. Adding 10% sodium carbonate solution to neutralize to pH 7.0-8.5, separating phases, washing organic layer with (1%) sodium bicarbonate for 3 times, drying with 50g anhydrous sodium sulfate, filtering to remove sodium sulfate crystals, removing toluene at 80 deg.C under 0.98 vacuum degree to obtain ethyl benzoate 586g (content 93%, gas chromatography quantitative analysis)

Step two

The operation process is as follows: the organic matter containing 149g (1.0 mol) of ethyl phenylmethanimidate, 113g of ethyl cyanoacetate (1.0 mol) and 0.1g of triethylamine are added into a four-mouth glass bottle of a condenser provided with a mechanical stirrer and a thermometer, the temperature is raised to 80 ℃, the mixture reacts for 2 hours at the temperature, then the temperature is raised to 100 ℃, the temperature is kept for 2 hours, then the temperature is raised to 120 ℃, the temperature is kept for 2 hours, then the temperature is raised to 140 ℃, the temperature is kept for 2 hours, and the ethanol and a small amount of toluene generated by the reaction are removed under the negative pressure of 3 mmHg. Following GC, the reaction product was decanted off to a ethyl phenylmethanimidate content of less than 0.5% to give 208G (GC) of ethyl 3-amino-3-phenyl-2-cyanoacrylate, 3.7g of triphenyls-triazine 95% pure (HPLC).

Example 4

Step one the procedure as described in example 3 was followed.

Step two

The reaction formula is as follows:

the operation process is as follows: in a four-neck glass bottle equipped with a condenser of a mechanical stirring thermometer, 149g (1.0 mol) of the organic matter containing ethyl phenylmethanimidate prepared in step one, 113g of ethyl cyanoacetate (1.0 mol) and 0.1g of triethylamine are added, the temperature is raised to 140 ℃, the reaction is carried out for 2 hours at the temperature, the temperature is kept for 4 hours, and simultaneously, ethanol and a small amount of toluene generated in the reaction are removed under the negative pressure of 3 mmHg. After the content of ethyl phenylmethanimidate was less than 0.5%, the reaction product was decanted off by GC to give ethyl 3-amino-3-phenyl-2-cyanoacrylate.

Example 5

The first step,

The reaction formula is as follows:

the operation process is as follows: the synthesis of ethyl 4-methylphenylmethyleneformiate was carried out according to J.HETERCYCLIC. chem.33.1903 (1996). 150g of hydrogen chloride gas was bubbled into a solution of about 4.0 moles of 4-methylbenzonitrile, 8.0 moles of ethanol in 2000ml of toluene at 5-10 ℃. And stirred at room temperature (25 ℃) for 20 hours to give a filtered white solid. Adding 10% sodium carbonate solution to neutralize to pH 7.0-8.5, separating phases, washing organic layer with (1%) sodium bicarbonate for 3 times, drying with 50g anhydrous sodium sulfate, filtering to obtain sodium sulfate crystal, removing toluene at 80 deg.C and 0.98 vacuum degree to obtain 4-methyl ethyl benzoate 586g (process content 93%, gas chromatography quantitative analysis)

Step two,

The operation process is as follows: in a four-mouth glass bottle provided with a condenser with a mechanical stirring thermometer, 163g (1.0 mol) of organic matter containing 4-methylphenylmethylidine ethyl ester, 113g of ethyl cyanoacetate (1.0 mol) and 0.1g of triethylamine are added, the mixture is heated to 80 ℃ and reacted for 2 hours at the temperature, then the temperature is heated to 100 ℃, the temperature is kept for 2 hours, then the temperature is heated to 120 ℃, the temperature is kept for 2 hours, then the temperature is kept for 140 ℃, the temperature is kept for 2 hours, and simultaneously the ethanol and a small amount of toluene generated by the reaction are removed at the temperature under the negative pressure of 3 mmHg. Following GC, the reaction product was decanted off to a ethyl phenylmethanimidate content of less than 0.5% to give 212g (mp 120 ℃ C.) of ethyl 3-amino-3-phenyl-2-cyanoacrylate with a purity of 95% (HPLC analysis) of 3.7g of tris (4-methyl) phenyl-s-triazine.

Example 6

The first step,

The reaction formula is as follows:

the operation process is as follows: the synthesis of ethyl 4-chlorophenylmethylimidate is described in J.heterocyclic. chem.33.1903 (1996). 150g of hydrogen chloride gas was bubbled into a solution of about 4.0 moles of 4-methylbenzonitrile, 8.0 moles of ethanol in 2000ml of toluene at 5-10 ℃. And stirred at room temperature (25 ℃) for 20 hours to give a filtered white solid. Adding 10% sodium carbonate solution to neutralize to pH 7.0-8.5, separating phases, washing organic layer with (1%) sodium bicarbonate for 3 times, drying with 50g anhydrous sodium sulfate, filtering to remove sodium sulfate crystals, removing toluene at 80 deg.C under 0.98 vacuum degree to obtain 602g of 4-chlorobenzoic acid ethyl ester (content 93%, gas chromatography quantitative analysis)

Step two,

The operation process is as follows: in a four-mouth glass bottle provided with a condenser with a mechanical stirring thermometer, 183.5g (1.0 mol) of organic matter containing 4-methylphenylmethylidine ethyl ester, 113g ethyl cyanoacetate (1.0 mol) and 0.1g triethylamine are added, the temperature is raised to 80 ℃, the mixture reacts for 2 hours at the temperature, then the temperature is raised to 100 ℃, the temperature is kept for 2 hours, then the temperature is raised to 120 ℃, the temperature is kept for 2 hours, then the temperature is raised to 140 ℃, the temperature is kept for 2 hours, and the ethanol and a small amount of toluene generated by the reaction are removed under the negative pressure of 3 mmHg. After the content of ethyl phenylmethanimidate was less than 0.5%, the reaction product was decanted off by GC to give 215g of ethyl 3-amino-3-phenyl-2-cyanoacrylate (mp 127-.

Example 7

The first step,

The reaction formula is as follows:

the operation process is as follows: ethylacetimidate synthesis was performed according to J.heterocyclic. chem.33.1903 (1996). 150g of hydrogen chloride gas was bubbled into a solution of about 4.0 moles of acetonitrile, 8.0 moles of isopropanol in 2000ml of toluene at 5-10 deg.C. And stirred at room temperature (25 ℃) for 20 hours to give a filtered white solid. Adding 10% sodium carbonate solution to neutralize to pH 7.0-8.5, separating phases, washing organic layer with (1%) sodium bicarbonate for 3 times, drying with 50g anhydrous sodium sulfate, filtering to remove sodium sulfate crystals, removing toluene at 80 deg.C under 0.98 vacuum degree to obtain 302g (content 93%, gas chromatography quantitative analysis)

Step two,

The operation process is as follows: in a four-mouth glass bottle provided with a condenser with a mechanical stirrer and a thermometer, 101g (1.0 mol) of the organic matter containing the ethyl acetimidate, 113g of ethyl cyanoacetate (1.0 mol) and 0.1g of triethylamine are added, the temperature is raised to 80 ℃, the mixture reacts for 2 hours at the temperature, then the temperature is raised to 100 ℃, the temperature is kept for 2 hours, then the temperature is raised to 120 ℃, the temperature is kept for 4 hours, the temperature is kept for 2 hours, and ethanol and a small amount of toluene generated by the reaction are removed under negative pressure under the vacuum degree of 0.98. After the content of ethyl acetimidate was less than 0.5% by GC tracing, the reaction product was decanted to give 215g of ethyl 3-amino-3-phenyl-2-cyanoacrylate (m.p. 127-.

Comparative example 1

Step one preparation by the reaction procedure of step 1 of example 1

Step two,

The reaction formula is as follows:

the operation process is as follows: in a four-necked glass bottle equipped with a condenser of a mechanical stirrer and a thermometer, 149g (1.0 mol) of the above organic material containing ethyl phenylmethanimidate, 113g of ethyl cyanoacetate (1.0 mol), 2000ml of toluene and 0.1g of triethylamine were charged, heated to 80 ℃ and reacted at this temperature for 2 hours, then heated to 100 ℃ and kept at this temperature for 2 hours, then heated to 110 ℃ and refluxed for 8 hours, and the conversion of ethyl phenylmethanimidate was reduced to 0 to 5 ℃ as usual to about 90% by GC, thereby obtaining 165g of ethyl 3-amino-3-phenyl-2-cyanoacrylate.

Comparative example 2

Step one following the reaction procedure of step 1 of example 1,

step two,

The reaction formula is as follows:

the operation process is as follows: in a four-necked glass bottle equipped with a condenser equipped with a mechanical stirrer and a thermometer, 149g (1.0 mol) of the organic material containing ethyl phenylmethanimidate, 99g (1.0 mol) of methyl cyanoacetate and 0.1g of triethylamine were charged, heated to 80 ℃ and reacted at this temperature for 2 hours, then heated to 100 ℃ and maintained at this temperature for 2 hours, then heated to 110 ℃ and maintained at this temperature for 2 hours, then further heated to 160 ℃ and maintained at this temperature for 2 hours, and the conversion of ethyl phenylmethanimidate was generally about 95% by GC tracing, but the reaction results were different each time when the organic material contained varying amounts of ethyl 3-amino-3-phenyl-2-cyanoacrylate and ethyl 3-amino-3-phenyl-2-cyanoacrylate (generally, the molar ratio was varied about 1: 1).

Comparative example 3

The first step,

Methyl phenylmethaneiminate is prepared according to J.heterocyclic. chem.33.1903 (1996),

step two,

Reaction type

In a four-necked glass bottle equipped with a condenser equipped with a mechanical stirrer and a thermometer, 135.0g (1.0 mol) of the above-mentioned organic substance containing methyl phenylmethanecarboximidate, 113.0g (1.0 mol) of ethyl cyanoacetate, 0.1g of triethylamine were charged, heated to 80 ℃ and reacted at this temperature for 2 hours, then heated to 100 ℃ and kept at this temperature for 2 hours, then further heated to 110 ℃ and kept at this temperature for 2 hours, then further heated to 160 ℃ and kept at this temperature for 2 hours, and the conversion of ethyl phenylmethanimidate was generally around 95% as followed by GC, but the reaction results were different each time when containing varying amounts of ethyl 3-amino-3-phenyl-2-cyanoacrylate and ethyl 3-amino-3-phenyl-2-cyanoacrylate (generally in a molar ratio of around 1: 1).

The 2-cyanoacrylate was synthesized in a similar manner by selecting different raw materials shown in the table.

Examples	Structural formula of compound	Similar examples	Content (wt.)	Melting Point	Yield (%)
						8		5	95%	118-120℃	90%
9		5	93%	117-118℃	80%
						10		5	92%	111-112℃	90%
11		5	91%	71-73℃	90%
						12		5	90%	132-134℃	90%
13		5	95%	118-120℃	80%